Open-source MasterGo alternatives

Penpot is an open-source design platform for teams building digital products. It runs in the browser or on your own servers, and its emphasis is ownership of the design infrastructure, which appeals to organizations with strict compliance or governance needs. It is often considered an open alternative to proprietary design tools such as Figma.

The platform uses open standards including SVG, CSS, HTML and JSON, so design files are closer to the code that implements them. Real-time collaboration lets designers and developers work together, and CSS Grid and Flex Layout let teams build responsive interfaces that behave like real layouts. Native design tokens act as a shared source of truth between design and development, which helps with larger design systems.

Penpot also exposes an open API and plugin system for automation and integrations, plus an MCP server for connecting AI workflows with design and code. It is written in Clojure and ClojureScript under the MPL-2.0 license, and a hosted version is available at penpot.app for teams that do not want to self-host.

OpenPencil is an open-source vector design tool built around AI agents. Instead of drawing every element by hand, you describe a design in a prompt and agents build the interface directly on a live canvas. The project presents itself as a modern alternative to Pencil and frames its approach as design-as-code.

Headline features include concurrent agent teams that work on a design in parallel, a built-in MCP server so external coding agents can drive the canvas, and support for multiple AI models and providers. Repository topics reference Claude Code, Codex and OpenCode, as well as output targets such as React, Flutter and React Native. The project is built mainly in Rust with a React front end.

OpenPencil is licensed under MIT, and its README is available in many languages. The input does not describe a hosted service, so it appears to be a tool you run on your own machine. It suits designers and developers experimenting with AI-driven UI creation.

Doop is an open-source alternative to Paper.design: a multiplayer design canvas for humans and AI agents. Each design lives on a shareable canvas that holds frames, which are artboards rendering real HTML in sandboxed iframes. People edit in the browser while AI agents edit through the built-in MCP server and stream their designs in live.

Everyone sees cursors, presence, frame edits, agent status and an activity feed as it happens. Clients such as Claude Code can connect once and sketch, stream and self-review designs next to your cursor, and a built-in Doop Agent can take cards or role mentions without any client. It runs on the server's Anthropic key for a few free tasks, then on a ChatGPT subscription or OpenAI key each user connects. Other features include comments pinned to elements, undo and redo, and a design memory that distills style rules agents follow.

Canvases are private by default, with access by email invitation or link sharing, and agents inherit their human's access. Doop is licensed under AGPL-3.0, written in TypeScript and built with bun. You can self-host with docker compose up, or run bun run dev with embedded Postgres and no other services.